1. Field of the Invention
This invention relates in general to a heat resistant and wear resistant iron-base sintered alloy as the material of a component part which requires heat resistance and wear resistance at high temperatures while exhibiting a low attacking ability and high concordance against an opposite member, and more particularly to the material suitable for a valve seat and a valve face of an engine valve and a waste gate valve of a turbocharger for an internal combustion engine.
2. Description of the Prior Art
In recent years, wear of component parts of an engine valve system for an internal combustion engine has become issue with requirement of increasing engine speed and engine power output, in which particularly valve seats require excellent oxidation resistance, friction characteristics and durability at high temperatures under severe high temperature engine combustion conditions. In this connection, a turbocharger is also required to be formed of a material durable in oxidation and friction at high temperatures.
Thus, since such component parts of the engine are subjected not only to high temperatures but also to friction and hammering, they are required to be formed of a material having high heat resistance, wear resistance and pitting resistance together with concordance with the material of an opposite member. Accordingly, such a high performance material has been eagerly desired.